Present day requirements for improved imaging devices place ever increasing demands on the accuracy of the alignment of cameras with respect to the objects to be viewed. Specifically, there is presently felt a need for a video camera for recording the visual stimuli received by the pilot of an aircraft, typically a fighter plane, for subsequent review for training purposes and/or in analysis of combat engagements. To be fully successful, the device recording the visual stimuli which the pilot sees must record what he sees with respect to the outside world, e.g. landing fields, other aircraft, aircraft carriers and the like, and must record the readings of the instruments which he can view. In the case of modern fighter aircraft, it is also desired that the pilot's movement of control and aiming devices for weaponry be accurately recorded.
It will be appreciated that aircraft are now being provided with "head up" instrument displays, in which holographic projections of certain instrument readings are provided superimposed over the pilot's field of view of the outside world, such that he does not have to look down to read the instruments. It is desired that these "head up" instrument readings be recorded as well.
To provide a complete and accurate record of what the pilot sees requires that the camera be very accurately aligned with respect to the airframe of the aircraft, that is, to its basic chassis. In particular, it is desired that this extreme accuracy of alignment of the camera with respect to the airframe be provided in connection with a camera which comprises a charge coupled device (CCD) image forming element.